In filling operations for sterile products, in particular when one aspires to a demanding license, such as an FDA license, conventional safety valves are often insufficient.
Conventional safety valves, as a rule, have a spring-loaded valve body that automatically opens at a certain limit pressure. These types of safety valves are known and have been described many times in patent literature, for example, EP 0 022 941 A1, EP 0 051 082 A1, DE 37 42 722 A1 and DE 196 07 840 C1, to name but a few.
In pipeline systems that are to be kept sterile, a surge creates the risk that the valve may open briefly to the non-sterile blow-off line. This can result in contamination. To reduce the risk of contamination when such conventional safety valves are used in filling processes for foodstuffs, in particular for beverages, the housing of the safety valve is continuously traversed by ambient pressure steam.
A disadvantage of the foregoing method is that a hot spot can develop in the pipeline network. Through heat conduction inside the metal pipeline, this hot spot leads to a temperature increase in more remote regions. But this temperature increase may not be enough to sterilize, but still enough to accelerate microbial growth. In addition, this solution wastes energy.
It is known to couple a rupture disc to a safety valve that is connected downstream. The rupture disc closes off in a more or less flush manner with the pipeline and is treated on one side by conventional cleaning and sterilizing routines. This solution makes it possible, in the event of the rupture disk breaking, to terminate the process in a controlled manner.
A disadvantage of the use of rupture discs is the costs involved when a rupture disc is lost and the subsequent time and money spent on labor and cleaning when a rupture disc has to be replaced. Consequently, it is an object of the invention to disclose a device that eliminates the abovementioned disadvantages.